This document serves as thecomplete definition of Google's coding standards forsource code in the Java™ Programming Language. A Java source file is described as beinginGoogle Style if and only if it adheres to the rules herein.
Like other programming style guides, the issues covered span not only aesthetic issues offormatting, but other types of conventions or coding standards as well. However, this documentfocuses primarily on thehard-and-fast rules that we follow universally, andavoids givingadvice that isn't clearly enforceable (whether by human or tool).
In this document, unless otherwise clarified:
@interface).Other "terminology notes" will appear occasionally throughout the document.
Example code in this document isnon-normative. That is, while the examplesare in Google Style, they may not illustrate theonly stylish way to represent thecode. Optional formatting choices made in examples should not be enforced as rules.
For a source file containing classes, the file name consists of the case-sensitive name of thetop-level class (of which there isexactly one), plus the.java extension.
Source files are encoded inUTF-8.
Aside from the line terminator sequence, theASCII horizontal spacecharacter (0x20) is the only whitespace character that appearsanywhere in a source file. This implies that:
For any character that has a special escape sequence(\b,\t,\n,\f,\r,\s,\",\' and\\), that sequenceis used rather than the corresponding octal(e.g. \012) or Unicode(e.g. \u000a) escape.
For the remaining non-ASCII characters, either the actual Unicode character(e.g. ∞) or the equivalent Unicode escape(e.g. \u221e) is used. The choice depends only onwhich makes the codeeasier to read and understand, although Unicode escapesoutside string literals and comments are strongly discouraged.
Tip: In the Unicode escape case, and occasionally even when actualUnicode characters are used, an explanatory comment can be very helpful.
Examples:
| Example | Discussion |
|---|---|
String unitAbbrev = "μs"; | Best: perfectly clear even without a comment. |
String unitAbbrev = "\u03bcs"; // "μs" | Allowed, but there's no reason to do this. |
String unitAbbrev = "\u03bcs"; // Greek letter mu, "s" | Allowed, but awkward and prone to mistakes. |
String unitAbbrev = "\u03bcs"; | Poor: the reader has no idea what this is. |
return '\ufeff' + content; // byte order mark | Good: use escapes for non-printable characters, and comment if necessary. |
Tip: Never make your code less readable simply out of fear thatsome programs might not handle non-ASCII characters properly. If that should happen, thoseprograms arebroken and they must befixed.
An ordinary source file consists of,in order:
Exactly one blank line separates each section that is present.
Apackage-info.java file is the same, but without the top-level class.
Amodule-info.java file does not contain a package statement and replaces thesingle top-level class with a module declaration, but otherwise follows the same structure.
If license or copyright information belongs in a file, it belongs here.
The package statement isnot line-wrapped. The column limit (Section 4.4,Column limit: 100) does not apply to package statements.
Wildcard imports, static or otherwise,are not used.
Import statements arenot line-wrapped. The column limit (Section 4.4,Column limit: 100) does not apply to importstatements.
Imports are ordered as follows:
If there are both static and non-static imports, a single blank line separates the twoblocks. There are no other blank lines between import statements.
Within each block the imported names appear in ASCII sort order. (Note:this is not the same as the importstatements being in ASCII sort order, since '.'sorts before ';'.)
Static import is not used for static nested classes. They are imported withnormal imports.
Each top-level class resides in a source file of its own.
The order you choose for the members and initializers of your class can have a great effect onlearnability. However, there's no single correct recipe for how to do it; different classes mayorder their contents in different ways.
What is important is that each class usessome logical order, which itsmaintainer could explain if asked. For example, new methods are not just habitually added to the endof the class, as that would yield "chronological by date added" ordering, which is not a logicalordering.
Methods of a class that share the same name appear in a single contiguous group with no othermembers in between. The same applies to multiple constructors (which always have the same name).This rule applies even when modifiers such asstatic orprivate differ between the methods.
Module directives are ordered as follows:
requires directives in a single block.exports directives in a single block.opens directives in a single block.uses directives in a single block.provides directives in a single block.A single blank line separates each block that is present.
Terminology Note:block-like construct refers tothe body of a class, method or constructor. Note that, by Section 4.8.3.1 onarray initializers, any array initializermay optionally be treated as if it were a block-like construct.
Braces are used withif,else,for,do andwhile statements, even when thebody is empty or contains only a single statement.
Other optional braces, such as those in a lambda expression, remain optional.
Braces follow the Kernighan and Ritchie style("Egyptian brackets")fornonempty blocks and block-like constructs:
else or a comma.Exception: In places where these rules allow a single statement ending with a semicolon(;), a block of statements can appear, and the openingbrace of this block is preceded by a line break. Blocks like these are typically introduced tolimit the scope of local variables.
Examples:
return () -> { while (condition()) { method(); }};return new MyClass() { @Override public void method() { if (condition()) { try { something(); } catch (ProblemException e) { recover(); } } else if (otherCondition()) { somethingElse(); } else { lastThing(); } { int x = foo(); frob(x); } }};A few exceptions for enum classes are given in Section 4.8.1,Enum classes.
An empty block or block-like construct may be in K & R style (as described inSection 4.1.2). Alternatively, it may be closed immediatelyafter it is opened, with no characters or line break in between({}),unless it is part of amulti-block statement (one that directly contains multiple blocks:if/else ortry/catch/finally).
Examples:
// This is acceptable void doNothing() {} // This is equally acceptable void doNothingElse() { } // This is not acceptable: No concise empty blocks in a multi-block statement try { doSomething(); } catch (Exception e) {}Each time a new block or block-like construct is opened, the indent increases by twospaces. When the block ends, the indent returns to the previous indent level. The indent levelapplies to both code and comments throughout the block. (See the example in Section 4.1.2,Nonempty blocks: K & R Style.)
Each statement is followed by a line break.
Java code has a column limit of 100 characters. A "character" means any Unicode code point.Except as noted below, any line that would exceed this limit must be line-wrapped, as explained inSection 4.5,Line-wrapping.
Each Unicode code point counts as one character, even if its display width isgreater or less. For example, if usingfullwidth characters,you may choose to wrap the line earlier than where this rule strictly requires.
Exceptions:
package andimport statements (see Sections 3.2Package statement and 3.3Import statements).Terminology Note: When code that might otherwise legallyoccupy a single line is divided into multiple lines, this activity is calledline-wrapping.
There is no comprehensive, deterministic formula showingexactly how to line-wrap inevery situation. Very often there are several valid ways to line-wrap the same piece of code.
Note: While the typical reason for line-wrapping is to avoidoverflowing the column limit, even code that would in fact fit within the column limitmaybe line-wrapped at the author's discretion.
Tip: Extracting a method or local variable may solve the problemwithout the need to line-wrap.
The prime directive of line-wrapping is: prefer to break at ahigher syntactic level. Also:
.)::)<T extends Foo & Bar>)catch (FooException | BarException e)).for ("foreach") statement.() that follows it.,) stays attached to the token that precedes it.MyLambda<String, Long, Object> lambda = (String label, Long value, Object obj) -> { ... };Predicate<String> predicate = str -> longExpressionInvolving(str);switch (x) { case ColorPoint(Color color, Point(int x, int y)) -> handleColorPoint(color, x, y); ...}Note: The primary goal for line wrapping is to have clearcode,not necessarily code that fits in the smallest number of lines.
When line-wrapping, each line after the first (eachcontinuation line) is indentedat least +4 from the original line.
When there are multiple continuation lines, indentation may be varied beyond +4 asdesired. In general, two continuation lines use the same indentation level if and only if theybegin with syntactically parallel elements.
Section 4.6.3 onHorizontal alignment addressesthe discouraged practice of using a variable number of spaces to align certain tokens withprevious lines.
A single blank line always appears:
A single blank line may also appear anywhere it improves readability, for example betweenstatements to organize the code into logical subsections. A blank line before the first member orinitializer, or after the last member or initializer of the class, is neither encouraged nordiscouraged.
Multiple consecutive blank lines are permitted, but never required (or encouraged).
Beyond where required by the language or other style rules, and apart from literals, comments andJavadoc, a single ASCII space also appears in the following placesonly.
if,for orcatch, from an open parenthesis (() that follows it on that lineelse orcatch, from a closing curly brace (}) that precedes it on that line{), with two exceptions:@SomeAnnotation({a, b}) (no space is used)String[][] x = {{"foo"}}; (no space is required between{{, by item 9 below)<T extends Foo & Bar>catch (FooException | BarException e):) in an enhancedfor ("foreach") statement(String str) -> str.length()case "FOO" -> bar();::) of a method reference, which is written likeObject::toString.), which is written likeobject.toString(),:; or the closing parenthesis ()) of a cast//) which begins a comment. Multiple spaces are allowed.//) which begins a comment and the comment's text. Multiple spaces are allowed.List<String> listnew int[] {5, 6} andnew int[] { 5, 6 } are both valid[] or....This rule is never interpreted as requiring or forbidding additional space at the start orend of a line; it addresses onlyinterior space.
Terminology Note:Horizontal alignment is thepractice of adding a variable number of additional spaces in your code with the goal of makingcertain tokens appear directly below certain other tokens on previous lines.
This practice is permitted, but isnever required by Google Style. It is noteven required tomaintain horizontal alignment in places where it was already used.
Here is an example without alignment, then using alignment:
private int x; // this is fineprivate Color color; // this tooprivate int x; // permitted, but future editsprivate Color color; // may leave it unaligned
Tip: Alignment can aid readability, but attempts to preservealignment for its own sake create future problems. For example, consider a change that touches onlyone line. If that change disrupts the previous alignment, it's important **not** to introduceadditional changes on nearby lines simply to realign them. Introducing formatting changes onotherwise unaffected lines corrupts version history, slows down reviewers, and exacerbates mergeconflicts. These practical concernstake priority over alignment.
Optional grouping parentheses are omitted only when author and reviewer agree that there is noreasonable chance the code will be misinterpreted without them, nor would they have made the codeeasier to read. It isnot reasonable to assume that every reader has the entire Javaoperator precedence table memorized.
After each comma that follows an enum constant, a line break is optional. Additional blanklines (usually just one) are also allowed. This is one possibility:
private enum Answer { YES { @Override public String toString() { return "yes"; } }, NO, MAYBE}An enum class with no methods and no documentation on its constants may optionally be formattedas if it were an array initializer (see Section 4.8.3.1 onarray initializers).
private enum Suit { CLUBS, HEARTS, SPADES, DIAMONDS }Since enum classesare classes, all other rules for formatting classes apply.
Every variable declaration (field or local) declares only one variable: declarations such asint a, b; are not used.
Exception: Multiple variable declarations are acceptable in the header of afor loop.
Local variables arenot habitually declared at the start of their containingblock or block-like construct. Instead, local variables are declared close to the point they arefirst used (within reason), to minimize their scope. Local variable declarations typically haveinitializers, or are initialized immediately after declaration.
Any array initializer mayoptionally be formatted as if it were a "block-likeconstruct." For example, the following are all valid (not an exhaustivelist):
new int[] { new int[] { 0, 1, 2, 3 0,} 1, 2,new int[] { 3, 0, 1, } 2, 3} new int[] {0, 1, 2, 3}The square brackets form a part of thetype, not the variable:String[] args, notString args[].
For historical reasons, the Java language has two distinct syntaxes forswitch, which we can callold-style andnew-style. New-style switches use an arrow(->) after the switch labels, while old-style switchesuse a colon (:).
Terminology Note: Inside the braces of aswitch block are either one or moreswitch rules (new-style);or one or morestatement groups (old-style). Aswitchrule consists of aswitch label (case ...ordefault) followed by-> and an expression, block, orthrow. A statement group consists of one or more switch labels each followed bya colon, then one or more statements, or, for thelast statement group,zero ormore statements. (These definitions match the Java Language Specification,§14.11.)
As with any other block, the contents of a switch block are indented +2. Each switch labelstarts with this +2 indentation.
In a new-style switch, a switch rule can be written on a single line if it otherwise followsGoogle style. (It must not exceed the column limit, and if it contains a non-empty block thenthere must be a line break after{.) The line-wrappingrules ofSection 4.5 apply, including the +4 indent forcontinuation lines. For a switch rule with a non-empty block after the arrow, the same rules applyas for blocks elsewhere: lines between{ and} are indented a further +2 relative to the line with theswitch label.
switch (number) { case 0, 1 -> handleZeroOrOne(); case 2 -> handleTwoWithAnExtremelyLongMethodCallThatWouldNotFitOnTheSameLine(); default -> { logger.atInfo().log("Surprising number %s", number); handleSurprisingNumber(number); }}In an old-style switch, the colon of each switch label is followed by a line break. Thestatements within a statement group start with a further +2 indentation.
Within an old-style switch block, each statement group either terminates abruptly (with abreak,continue,return or thrown exception), or is marked with a commentto indicate that execution will ormight continue into the next statement group. Anycomment that communicates the idea of fall-through is sufficient (typically// fall through). This special comment is not required inthe last statement group of the switch block. Example:
switch (input) { case 1: case 2: prepareOneOrTwo(); // fall through case 3: handleOneTwoOrThree(); break; default: handleLargeNumber(input);}Notice that no comment is needed aftercase 1:, onlyat the end of the statement group.
There is no fall-through in new-style switches.
default labelThe Java language requires switch expressions and many kinds of switch statements to beexhaustive. That effectively means that every possible value that could be switched on willbe matched by one of the switch labels. A switch is exhaustive if it has adefault label, but also for example if the value being switchedon is an enum and every value of the enum is matched by a switch label. Google Style requiresevery switch to be exhaustive, even those where the language itself does not require it.This may require adding adefault label, even if itcontains no code.
Switch expressions must be new-style switches:
return switch (list.size()) { case 0 -> ""; case 1 -> list.getFirst(); default -> String.join(", ", list); };Type-use annotations appear immediately before the annotated type. An annotation is a type-useannotation if it is meta-annotated with@Target(ElementType.TYPE_USE). Example:
final @Nullable String name;public @Nullable Person getPersonByName(String name);
Annotations applying to a class, package, or module declaration appear immediately after thedocumentation block, and each annotation is listed on a line of its own (that is, one annotationper line). These line breaks do not constitute line-wrapping (Section4.5,Line-wrapping), so the indentation level is notincreased. Examples:
/** This is a class. */@Deprecated@CheckReturnValuepublic final class Frozzler { ... }/** This is a package. */@Deprecated@CheckReturnValuepackage com.example.frozzler;
/** This is a module. */@Deprecated@SuppressWarnings("CheckReturnValue")module com.example.frozzler { ... }The rules for annotations on method and constructor declarations are the same as theprevious section. Example:
@Deprecated@Overridepublic String getNameIfPresent() { ... }Exception: Asingle parameterless annotationmay instead appear together with the first line of the signature, for example:
@Override public int hashCode() { ... }Annotations applying to a field also appear immediately after the documentation block, but inthis case,multiple annotations (possibly parameterized) may be listed on the same line;for example:
@Partial @Mock DataLoader loader;
There are no specific rules for formatting annotations on parameters or local variables (except,of course, when the annotation is a type-use annotation).
This section addressesimplementation comments. Javadoc is addressed separately inSection 7,Javadoc.
Any line break may be preceded by arbitrary whitespace followed by an implementation comment.Such a comment renders the line non-blank.
Block comments are indented at the same level as the surrounding code. They may be in/* ... */ style or// ... style. For multi-line/* ... */ comments, subsequent lines must start with* aligned with the* on the previous line.
/* * This is // And so /* Or you can * okay. // is this. * even do this. */ */
Comments are not enclosed in boxes drawn with asterisks or other characters.
Tip: When writing multi-line comments, use the/* ... */ style if you want automatic code formatters tore-wrap the lines when necessary (paragraph-style). Most formatters don't re-wrap lines in// ... style comment blocks.
UseTODO comments for code that is temporary, a short-term solution, or good-enough but not perfect.
ATODO comment begins with the wordTODO in all caps, a following colon, and a link to a resource that contains the context, ideally a bug reference. A bug reference is preferable because bugs are tracked and have follow-up comments. Follow this piece of context with an explanatory string introduced with a hyphen-.
The purpose is to have a consistentTODO format that can be searched to find out how to get more details.
// TODO: crbug.com/12345678 - Remove this after the 2047q4 compatibility window expires.
Avoid adding TODOs that refer to an individual or team as the context:
// TODO: @yourusername - File an issue and use a '*' for repetition.
If yourTODO is of the form "At a future date do something" make sure that you either include a very specific date ("Fix by November 2005") or a very specific event ("Remove this code when all clients can handle XML responses.").
Class and member modifiers, when present, appear in the orderrecommended by the Java Language Specification:
public protected private abstract default static final sealed non-sealed transient volatile synchronized native strictfp
Modifiers onrequires module directives, when present, appear in the followingorder:
transitive static
long-valued integer literals use an uppercaseL suffix, neverlowercase (to avoid confusion with the digit1). For example,3000000000Lrather than3000000000l.
The opening""" of a text block is always on a new line. That line may either follow the same indentation rules as other constructs, or it may have no indentation at all (so it starts at the left margin). The closing""" is on a new line with the same indentation as the opening""", and may be followed on the same line by further code. Each line of text in the text block is indented at least as much as the opening and closing""". (If a line is indented further, then the string literal defined by the text block will have space at the start of that line.)
The contents of a text block may exceed thecolumn limit.
Identifiers use only ASCII letters and digits, and, in a small number of cases noted below,underscores. Thus each valid identifier name is matched by the regular expression\w+ .
In Google Style, special prefixes or suffixes arenot used. For example, thesenames are not Google Style:name_,mName,s_name andkName.
Package and module names use only lowercase letters and digits (no underscores). Consecutivewords are simply concatenated together. For example,com.example.deepspace, notcom.example.deepSpace orcom.example.deep_space.
Class names are written inUpperCamelCase.
Class names are typically nouns or noun phrases. For example,Character orImmutableList. Interface names may also be nouns ornoun phrases (for example,List), but may sometimes beadjectives or adjective phrases instead (for example,Readable).
There are no specific rules or even well-established conventions for naming annotation types.
Atest class has a name that ends withTest,for example,HashIntegrationTest.If it covers a single class, its name is the name of that classplusTest, for exampleHashImplTest.
Method names are written inlowerCamelCase.
Method names are typically verbs or verb phrases. For example,sendMessage orstop.
Underscores may appear in JUnittest method names to separate logical components of thename, witheach component written inlowerCamelCase, forexampletransferMoney_deductsFromSource. There is no OneCorrect Way to name test methods.
Constant names useUPPER_SNAKE_CASE: all uppercaseletters, with each word separated from the next by a single underscore. But whatis aconstant, exactly?
Constants are static final fields whose contents are deeply immutable and whose methods have nodetectable side effects. Examples include primitives, strings, immutable value classes, and anythingset tonull. If any of the instance's observable state can change, it is not aconstant. Merelyintending to never mutate the object is not enough. Examples:
// Constantsstatic final int NUMBER = 5;static final ImmutableList<String> NAMES = ImmutableList.of("Ed", "Ann");static final Map<String, Integer> AGES = ImmutableMap.of("Ed", 35, "Ann", 32);static final Joiner COMMA_JOINER = Joiner.on(','); // because Joiner is immutablestatic final SomeMutableType[] EMPTY_ARRAY = {};// Not constantsstatic String nonFinal = "non-final";final String nonStatic = "non-static";static final Set<String> mutableCollection = new HashSet<String>();static final ImmutableSet<SomeMutableType> mutableElements = ImmutableSet.of(mutable);static final ImmutableMap<String, SomeMutableType> mutableValues = ImmutableMap.of("Ed", mutableInstance, "Ann", mutableInstance2);static final Logger logger = Logger.getLogger(MyClass.getName());static final String[] nonEmptyArray = {"these", "can", "change"};These names are typically nouns or noun phrases.
Non-constant field names (static or otherwise) are writteninlowerCamelCase.
These names are typically nouns or noun phrases. For example,computedValues orindex.
Parameter names are written inlowerCamelCase.
One-character parameter names in public methods should be avoided.
Local variable names are written inlowerCamelCase.
Even when final and immutable, local variables are not considered to be constants, and should notbe styled as constants.
Each type variable is named in one of two styles:
E,T,X,T2)T (examples:RequestT,FooBarT).Sometimes there is more than one reasonable way to convert an English phrase into camel case,such as when acronyms or unusual constructs like "IPv6" or "iOS" are present. To improvepredictability, Google Style specifies the following (nearly) deterministic scheme.
Beginning with the prose form of the name:
In very rare circumstances (for example, multipart version numbers), you may need to useunderscores to separate adjacent numbers, since numbers do not have upper and lower case variants.
Examples:
| Prose form | Correct | Incorrect |
|---|---|---|
| "XML HTTP request" | XmlHttpRequest | XMLHTTPRequest |
| "new customer ID" | newCustomerId | newCustomerID |
| "inner stopwatch" | innerStopwatch | innerStopWatch |
| "supports IPv6 on iOS?" | supportsIpv6OnIos | supportsIPv6OnIOS |
| "YouTube importer" | YouTubeImporterYoutubeImporter* | |
| "Turn on 2SV" | turnOn2sv | turnOn2Sv |
| "Guava 33.4.6" | guava33_4_6 | guava3346 |
*Acceptable, but not recommended.
Note: Some words are ambiguously hyphenated in the Englishlanguage: for example "nonempty" and "non-empty" are both correct, so the method namescheckNonempty andcheckNonEmpty are likewise both correct.
@Override: always usedA method is marked with the@Override annotationwhenever it is legal. This includes a class method overriding a superclass method, a class methodimplementing an interface method, an interface method respecifying a superinterface method, and anexplicitly declared accessor method for a record component.
Exception:@Override may be omitted when the parent method is@Deprecated.
It is very rarely correct to do nothing in response to a caughtexception. (Typical responses are to log it, or if it is considered "impossible", rethrow it as anAssertionError.)
When it truly is appropriate to take no action whatsoever in a catch block, the reason this isjustified is explained in a comment.
try { int i = Integer.parseInt(response); return handleNumericResponse(i);} catch (NumberFormatException ok) { // it's not numeric; that's fine, just continue}return handleTextResponse(response);When a reference to a static class member must be qualified, it is qualified with that class'sname, not with a reference or expression of that class's type.
Foo aFoo = ...;Foo.aStaticMethod(); // goodaFoo.aStaticMethod(); // badsomethingThatYieldsAFoo().aStaticMethod(); // very bad
Do not overrideObject.finalize. Finalization supportisscheduled for removal.
Thebasic formatting of Javadoc blocks is as seen in this example:
/** * Multiple lines of Javadoc text are written here, * wrapped normally... */public int method(String p1) { ... }... or in this single-line example:
/** An especially short bit of Javadoc. */
The basic form is always acceptable. The single-line form may be substituted when the entiretyof the Javadoc block (including comment markers) can fit on a single line. Note that this onlyapplies when there are no block tags such as@param.
One blank line—that is, a line containing only the aligned leading asterisk(*)—appears between paragraphs, and before the group of block tags if present.Each paragraph except the first has<p> immediately before the first word, withno space after it. HTML tags for other block-level elements, such as<ul> or<table>, arenot preceded with<p>.
Any of the standard "block tags" that are used appear in the order@param,@return,@throws,@deprecated, and these four types neverappear with an empty description. When a block tag doesn't fit on a single line, continuation linesare indented four (or more) spaces from the position of the@.
Each Javadoc block begins with a briefsummary fragment. Thisfragment is very important: it is the only part of the text that appears in certain contexts such asclass and method indexes.
This is a fragment—a noun phrase or verb phrase, not a complete sentence. It doesnot begin withA {@code Foo} is a..., orThis method returns..., nor does it form a complete imperative sentencelikeSave the record.. However, the fragment is capitalized andpunctuated as if it were a complete sentence.
Tip: A common mistake is to write simple Javadoc in the form/** @return the customer ID */. This isincorrect, and should be changed to/** Returns the customer ID. */ or/** {@return the customer ID} */.
At theminimum, Javadoc is present for everyvisible class, member, or recordcomponent, with a few exceptions noted below. A top-level class is visible if it ispublic; a member is visible if it ispublic orprotected and its containingclass is visible; and a record component is visible if its containing record is visible.
Additional Javadoc content may also be present, as explained in Section 7.3.4,Non-required Javadoc.
Javadoc is optional for "simple, obvious" members and record components, such as agetFoo() method,if therereally andtruly is nothing else worthwhile to say but "the foo".
Important: it is not appropriate to cite this exception to justifyomitting relevant information that a typical reader might need to know. For example, for a recordcomponent namedcanonicalName, don't omit itsdocumentation (with the rationale that it would say only@param canonicalName the canonical name) if a typical reader may haveno idea what the term "canonical name" means!
Javadoc is not always present on a method that overrides a supertype method.
Other classes, members, and record components have Javadocas needed or desired.
Whenever an implementation comment would be used to define the overall purpose or behavior of aclass or member, that comment is written as Javadoc instead (using/**).
Non-required Javadoc is not strictly required to follow the formatting rules of Sections7.1.1, 7.1.2, 7.1.3, and 7.2, though it is of course recommended.